2nd Black crystal is acquired by completing 9th challenge in under 1:00. The other one is found during the game. There is NOT a cheat that unlocks all the crystals, you have to get gold on some of the challenges but to be honest that dont impress me, the black one disintegrates but usually right as im killing the guy anyways. both defense sabers for me, but the black ones just look awesome.

To get some (notice “some” not all) secondary lightsaber cystals. You have to complete challenges with a silver or gold medal. Getting Bronze gives EXP points: Silver gives cystal and EXP if not already unlocking the EXP for that challenge; Gold gives you a new costume(pretty cool blowing up people as Boba Fett); and Platinum is just awesome and gives you everything listed before. It also gives you an achievment/trophy. I thought the easiest challenge to get platinum on whats the deflection trial. BTW, just getting bronze also gets you a cinematic, but you know, what a big deal that is (yawns).